Fable 5 vs 5.1.
What changes your cost?
Start with a synthetic example. Choose a category to change its tokens. Separate the new rate from a different amount of work.
$42.50at Fable 5 rates, compared with$27.50at Fable 5.1 rates
USD · same countsThe ring divides Fable 5 baseline dollars, not tokens. The text beside each category gives its subtotal rounded to cents.
Cache reads
$1 → $0.25 per million tokens
Use cache_read_input_tokens. Enter whole tokens, without commas. The same count is used for both models.
$42.50 → $27.50 · $15.00 lower token cost
One change. Two causes.
Rate effect−$15.00Original usage, new rates
Usage effect$0.00Changed usage, new rates
Net change−$15.00New cost minus old cost
The cache-read rate changes $42.50 to $27.50. Counts are unchanged, so the usage effect is zero.
Change the example, not the story.
Each preset is invented to isolate one cause. None is a measured model benchmark.
For the starting counts, 300,000 additional output tokens would exactly use up the $15 cache saving, if every other count stayed fixed.
See all token counts and category costs
| Category | 5 tokens | 5 cost | 5.1 tokens | 5.1 cost |
|---|---|---|---|---|
| Fresh input | 1,000,000 | $10.00 | 1,000,000 | $10.00 |
| 5-minute writes | 200,000 | $2.50 | 200,000 | $2.50 |
| 1-hour writes | 0 | $0.00 | 0 | $0.00 |
| Cache reads | 20,000,000 | $20.00 | 20,000,000 | $5.00 |
| Output | 200,000 | $10.00 | 200,000 | $10.00 |
Displayed money is rounded to cents; the download retains exact totals. Tiny changes can be below one cent.
Count a comparable piece of work.
Use two completed runs of the same task population if you want to compare real usage. A week with twice the traffic is a different comparison from the same requests on a new model. Include every request and retry in the chosen scope; do not mix averages per call with totals per task.
This instrument prices only the five token categories shown. It does not predict how either model will behave, connect to an account, explain subscription limits or calculate a complete invoice. Standard global Claude API list rates, checked . Counter mapping, rates and exclusions.